2011 HM102 orbits the Sun with a semi-major axis of 30.219 AU at a distance of 27.7–32.8 AU once every 166 years and 1 month (60,675 days). Its orbit has an eccentricity of 0.08 and an inclination of 29° with respect to the ecliptic.[1] Among the first 17 Neptune trojans discovered so far, it is the one with the highest inclination.[3]
Based on a generic magnitude-to-diameter conversion, it measures approximately 100 kilometers in diameter using an absolute magnitude of 8.1 and an assumed albedo of 0.10.[4] It is an averaged-sized body among the first 17 Neptune trojans discovered so far, which measure between 60 and 200 kilometers (for an absolute magnitude of 9.3–6.6 and an assumed albedo of 0.10).[3][4]
Observations with NIRSpec showed that the spectrum of 2011 HM102 does not exhibit clear Triton-like ice tholin features. The surface is likely covered in a thin layer of water ice and CO2 ice. Due to the variable color classification of this object, it is suspected that inhomogeneities in the surface composition exist.[6]
Due to its orbital uncertainty, this minor planet has not been numbered and its official discoverers have not been determined.[1][2] If named, it will follow the naming scheme already established with 385571 Otrera, which is to name these objects after figures related to the Amazons, an all-female warrior tribe that fought in the Trojan War on the side of the Trojans against the Greek.[7]
In October 2012, 2011 HM102 was the closest known object of any kind to the New Horizons spacecraft.[8] In mid- to late 2013, New Horizons passed within 1.2 AU of 2011 HM102, where it would be detectable with one of the onboard instruments.[5] An observation from New Horizons would measure the phase curveof2011 HM102 at phase angles unobtainable from Earth. The New Horizons team eventually decided that they would not target 2011 HM102 for observations because the preparations for the Pluto approach took precedence.[9]
^Markwardt, Larissa; Holler, Bryan J.; Lin, Hsing Wen; Gerdes, David W.; Adams, Fred C.; Malhotra, Renu; Napier, Kevin J. (6 October 2023). "First Near-IR Spectroscopic Survey of Neptune Trojans with JWST: Distinct Surface Compositions of Red vs Ultra-Red Neptune Trojans". arXiv:2310.03998 [astro-ph.EP].
